Line Circuit Research Articles

Six Phase Transmission Line Protection Using Bat Algorithm Tuned Stacked Sparse Autoencoder

Six-phase transmission lines have the capability to address the continually evolving power demand. It allows upgrading the power transfer capability of the prevailing three-phase double circuit line without major changes in the transmission corridors. However, the operational performance of any six-phase system is highly dependent on its protection scheme. The possibility of larger number of faults in six-phase system complicates the protection task. Furthermore, the harmonics intrusion arising because of nonlinear loading compromises the reliability of the conventional threshold-based protection schemes. In this regard, this article addresses the above-mentioned challenges by developing a protection scheme based on the hybrid frameworks of bat algorithm and stacked sparse autoencoder-deep neural network (SAE-DNN). To overcome the limitation of SAE-DNN regarding optimal selection of architecture and tuning parameters, the selection task has been formulated as an optimization problem and solved using Bat algorithm. The use of raw voltage and current signals as input to the SAE-DNN reduces the overall complexity of the protection scheme. The efficacy of the proposed scheme has been validated for all 120 types of faults under varying operating, loading and fault scenarios. Furthermore, the proposed scheme has been validated for practical settings by performing real-time simulations on OPAL-RT digital simulator.

Utilization of Arduino on Electric Motor Starting

The development of technology in the industrial world 4.0 is very fast, in particular it can be seen in the rapidly growing remote control system, the use of applications via the network is increasing, and so on. Remote control such as the use of Arduino with an internet network that can be used as a tool to provide information and receive information so that the industry can save in terms of time, employees and other operational costs. This paper aims to utilize Arduino as a tool in controlling electric motor starting which is operated via bylink. The results showed that by utilizing Arduino which was controlled from Bylink via a smartphone, it was able to operate an electric motor starting with a direct on line circuit, a wye-delta circuit and a sequential motor circuit.

Altered Cellular Sedimentation during Apheresis Impacts Outcomes of Peripheral Blood Stem Cell Collection Efficiency in Patients with Sickle Cell Disease

Recent reports have demonstrated the potential for gene therapy as a therapeutic option to achieve a durable cure in patients with sickle cell disease (SCD). However, for these emerging cell therapies, relatively large numbers of peripheral blood hematopoietic stem cells (PB HSCs) are required to generate a therapeutic dose. Outcomes of stem cell collections in patients with SCD are highly variable, at times yielding far fewer numbers of HSCs in the product than predicted by the number of PB CD34+ cells. While the CXCR4 antagonist plerixafor has emerged as a safe and reliable drug to mobilize CD34+ cells in patients with SCD, collection failures continue to occur requiring additional cycles or failure to generate a gene therapy product. We sought to understand the mechanics affecting stem cell sedimentation in real time and posited that SCD disease associated changes to red cells results in altered HSC sedimentation during apheresis, negatively impacting collection. Methods Autologous PB stem cell collections were performed in patients with SCD following mobilization with 240ug/kg plerixafor. To uncover the mechanisms impacting apheresis efficiency for collecting PB HSCs, we devised a method to interrogate the sedimentation of cells in peripheral blood in real time, by interrupting the return collection circuit line. Cellular composition analyses of the collecting interfaces were performed including CD34+ enumeration by flow cytometry, CBC and differential, reticulocyte counts, and surface CD47 expression of red blood cells (RBCs). Results Patients were mobilized with 240ug/kg of plerixafor up to 6 hours before apheresis collection. We collected fewer cells than predicted (3.78 million cells/kg) in these patients with an overall average apheresis collection efficiency of 38%, and a strikingly wide range of 2%-107%. We determined that the lower collection efficiency outcomes were primarily derived when using standard apheresis interface settings. The pre-apheresis PB CD34+ counts were less predictive of total CD34+ cells collected (p=0.012) in patients with SCD (r2=0.2557, p=0.0023) when compared to historical control patients without SCD (r2=0.7638, p<0.0001). Real time measurement of cell counts at standard (Hematocrit 3%, S) and deep (Hematocrit 5%, D) collecting interfaces of the apheresis machine showed a significant decrease in lymphocytes (p=0.0146), increase in monocytes (p=0.0496), and increase enrichment in CD34+ cells at the D interface (Panel A). Enrichment of CD34+ cells correlated with monocyte enrichment and (n=21, r2=0.6706, p<0.0001) and an increased fold change in CD34+ cells between the S and D interfaces correlated with higher PB reticulocyte percentage (r2=0.5295, p=0.0111). Further analysis of the individual collection interfaces revealed that most RBCs were HbS containing despite a PB HbS concentration <30%, consistent with an enrichment for shorter lived sickle red cells. CD47 expression has been previously reported in higher concentrations on the surface of younger RBCs during erythropoiesis. Surface expression of CD47 was found to be significantly higher at both the S and D interfaces compared to the PB of patients, indicating that the accumulation of a younger population of RBCs at the collecting interfaces. As microcytic RBCs have been associated with poor collection efficiencies, the SCD red cell hemoglobin concentration in the PB was used as a marker for size and a significant correlation was determined (r2=0.6086, p=0.0001). Patients with SCD can mobilize PB HSC in response to plerixafor but demonstrate specific characteristics that impede the collection of stem cells. During apheresis, CD34+ stem cells sediment at a deeper hematocrit interface in the buffy coat as a result of displacement by the younger patient-derived population of RBCs. The relative shift in erythrocyte sedimentation requires a corresponding alteration in collection strategies to improve the collection efficiency. In addition to red cell age, other factors that affect red cell buoyancy including iron status or additional globin gene mutations negatively impact apheresis stem cell collections. Full assessment of red cell parameters can identify patients that are at risk for poor stem cell collection outcomes. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Power Flow Modeling of Multi-Circuit Transmission Lines

To reduce the allocation of land for the construction of electric power facilities, it is possible to leverage multi-circuit overhead transmission lines (MCTLs), in which the conductors of several circuits of different voltage classes are placed on the same tower. The unique features of the arrangement of conductors on MCTL towers cause unequal inductances and capacitances of different phases. In addition, there are significant mutual electromagnetic influences on the line circuits. To account for these factors, it is advisable to model the power flow of electric power systems equipped with MCTLs using the phase frame of reference. On the basis of such models, it is possible to determine the power flows while taking into account lateral and transverse asymmetries and to analyze electromagnetic safety conditions along the routes of multi-circuit transmission lines. We proposed a technique for modeling power flows and electromagnetic fields of multi-circuit power transmission lines, in which conductors of several circuits of different voltage classes are placed on the same tower. The methodology is based on the application of phase coordinates, which are the most natural description of three-phase power systems. The method is versatile enough to be applied to solving the specified problems for MCTLs of different designs. The article presents the results of research aimed at developing a method for modeling MCTL power flows. The results of modeling power flows of an electrical network including a three-circuit power transmission line are presented. The practical use of the models developed by the authors will make it possible to make well-grounded choices regarding the options for the use of multi-circuit power lines.

Interpolatory proper order decomposition of nonlinear transmission line circuits

PurposeThe paper is concerned with interpolatory proper orthogonal decomposition (IPOD) methods for nonlinear transmission line circuits. This paper aims to examine several factors that must be considered when applying such model reduction techniques to this kind of circuit.Design/methodology/approachTwo types of POD will be implemented. In each case, the choice of the order of the reduced model and the order of the interpolation space shall be considered. The stability of the models shall be explored.FindingsThe results indicate that the order for the reduced model to obtain accurate results depends on the chosen method when considering nonlinear transmission lines. The results also indicate that the structure of the nonlinear transmission line is crucial for determining the stability of the reduced models.Originality/valueThe work compares two IPOD methods and discusses the issues involved in achieving an accurate and stable reduced-order model for a nonlinear transmission line.

Impedance Well Effect From Circuit Analysis and New Design Concepts for Ultrabroadband Passive Absorber

The limitation in enhancing the absorption bandwidth of a microwave absorber with a thin thickness in the ultrahigh-frequency (UHF) band has become an important challenge in the electromagnetic scattering field. Therefore, in this study, a new design concept of a single-layer impedance-well (IW) passive absorber is put forward for the first time, which exhibits enhanced absorption bandwidth and effectively approaches the Rozanov thickness limit for passive absorbers. The design concept proposed in this study is explained by using the transmission line theory and circuit analysis. Furthermore, the input impedance and electric field distribution of the IW absorber are systematically analyzed to demonstrate the existence of the IW effect and the predicted functionalities of the IW absorber. The simulated and measured results reveal that the designed absorber with the IW effect can obtain an absorption band over 0.45–2.34 GHz range with a bandwidth ratio (BWR) of 5.2 (135.5%) at a minimum reflectivity reduction of −10 dB under normal incidence. In addition, the thickness is reduced to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.069 \lambda _{{\mathrm {L}}}$ </tex-math></inline-formula> , which <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{{\mathrm {L}}}$ </tex-math></inline-formula> is the wavelength at the lowest operating frequency.

AlScN-Based SAW Magnetic Field Sensor for Isolated Closed-Loop Hysteretic Current Control of Switched-Mode Power Converters

This letter uses a surface acoustic wave magnetic field sensor for measurement and closed-loop current control of the inductor current in a GaN-based dc-dc power converter. The sensor is based on aluminium scandium nitride thin films with relatively high Sc concentration of 32% and fabricated on low-cost 8-in silicon substrate, with a magnetostrictive FeCoSiB film on top of a SAW delay line. The device has dc and bidirectional current measurement capability (derived from the magnetic flux density around a current trace) and is operated electrically isolated above the current trace. With permanent magnets as magnetic bias, the setup has a usable bidirectional current range of ±5 A. A phase detector IC measures the phase shift between the 296 MHz, 19 dBm input, and 35 dB attenuated output signal of the delay line sensor. The active sensor area has a distance of 2.5 mm from the current trace. In a 1.2 mT bias, the sensor is operated with a sensitivity of 18.28°/mT and bipolar current range of up to ±5 A. The sensor signal is enhanced by an analog filter to compensate the over 1 µs delay from the delay line and readout circuit. Finally, the sensor is used as the input of an analog hysteretic current control loop. The closed-loop current control operation is demonstrated using a 48 V GaN-based half-bridge dc-dc converter with 16 kHz triangular inductor current.

Time-Domain Techniques for Line Protection Using Three-Dimensional Cartesian Coordinates

Today high speed protection of power system elements is necessary and realizable. This paper introduces time-domain protection techniques for transmission lines using voltage and current signals in Cartesian coordinates. Three techniques are proposed using this approach for line protection. Direction of fault is obtained using change in angle between Cartesian planes of voltage and current. In the second application on unit protection scheme, internal and external faults in transmission lines are discriminated using dot product of the normals to both end current planes. Fault type identification is obtained using the angle between incremental changes in currents in Cartesian coordinates. The output of each protection function using the new concept is derived in a quarter-cycle. The performance of each of the proposed techniques is tested for load variation, high resistance fault, different fault types, power swing, fault inception angles and signal with noise. Further, the proposed techniques are evaluated using field data from a 400 kV double circuit line.

A distance protection approach for untransposed parallel transmission lines in case of phase-phase-ground inter-circuit faults

Distance relays’ phase and ground elements at either circuits of the parallel transmission lines undergo miscalculation of the correct fault impedance when facing inter-circuit faults. This paper proposes a distance protection approach for untransposed parallel lines in case of phase-phase-ground inter-circuit faults, which can also be served as the fault locator as its auxiliary function. It is a demanding task compared to that of transposed lines due to the mutual coupling between all six phases of the line circuits. Considering the intended faults with the fault arc and ground resistances, the line circuit model is analyzed on a time-domain basis, resulting an equation that is mathematically a linear combination of designated functions. This would provide a great chance of establishing an adaptive linear combiner with windowed inputs (W-Adaline) in consistence with the equation derived. The W-Adaline with its simple structure is capable of giving a fast and accurate estimation of the fault distance in an online manner, which is exploited for both the line distance protection and fault location. The proposed approach is readily implementable and is independent of the system configuration. It operates robustly in high-ground resistance, variable fault arc resistance and noisy conditions. Through extensive simulation studies in PSCAD/EMTDC, performance of the proposed approach would be investigated and verified in a variety of fault and system loading conditions.

Mitigation of common mode failures at multi-circuit line configurations by application of line arresters against back-flashovers

Due to the limited number of corridors multi circuit line configurations are often applied. These overhead lines frequently consist of high towers that are subject to lightning strokes. In case of higher current amplitudes and higher footing resistances due to bad earthing conditions back-flashovers are caused leading to common mode failures and to severe outages. The paper describes investigations performed by means of computer simulations to identify the towers of a multi-circuit line consisting of voltage levels 380 kV, 220 kV and 110 kV that are endangered by back-flashovers of the 110-kV double-circuit lines. The footing resistance of towers of the targeted line section has been measured by an instrument at high-frequency. Influence of various factors on the back-flashover over 110 kV insulator strings has been studied by means of EMTP-ATP simulations. Different current waveforms of the lightning stroke have been used to represent the first stroke and subsequent strokes. The towers are represented by the models described in [3], [8]. Available flashover analysis methods [7], [8], [12], [13] like leader development method by Pigini et al and by Motoyama, and voltage-time integration method by Kind have been applied. The towers at which back-flashover is more likely to occur than at other towers are identified by the time integral of voltage according to Kind. Various factors like tower footing impedance, tower surge impedance and tower height are considered. Application of line a surge arrester is shown to be a successful mitigation technique to reduce the back-flashover rate of those 110 kV lines. The lightning overvoltage performance of surge arresters has been analyzed by means of digital simulations. Based on the results of investigations line arresters were installed on the towers in question. Since the installation no further common mode failure has been observed.

Reversible Circuit Synthesis Method Using Sub-graphs of Shared Functional Decision Diagrams

Abstract Reversible circuit synthesis methods based on decision diagrams achieve low quantum costs but do not account for quantum bit (qubit) limits for the application of reversible logic in quantum computing. Here, a synthesis method using sub-graphs of shared functional decision diagrams (SFDDs) is proposed for reducing the number of lines when synthesizing reversible circuits. An SFDD is partitioned into sub-graphs by exploiting the longest dominant-active paths, and the sub-graphs are mapped to reversible gate cascades. To further reduce the number of lines, template root matching is presented for reusing circuit lines. Experimental results indicate that the proposed method achieves the known minimum number of lines in many cases and has good scalability. Although the proposed method increases the quantum cost over a prior method based on functional decision diagrams, it significantly reduces the number of lines in most cases. Compared with the one-pass method using quantum multiple-valued decision diagrams, the proposed method reduces the quantum cost without increasing the number of lines in many cases. When compared with the lookup table-based method using a direct mapping flow, the method reduces the number of lines in a few cases. Thus, the method aids in the physical realization of a quantum circuit.

Stripline Multilayer Devices Based on Complementary Split Ring Resonators.

A new analytic design for multilayer stripline devices in planar circuit technology is presented. The Complementary Split Ring Resonator (CSRR) is used as a sub-wavelength resonant particle, which provides high-Q resonances in a compact size. The electromagnetic field distribution achieved along the stripline enables enhanced excitation of the resonators. An optimal solution for multilayer power dividers is presented, in a configuration in which each output is obtained in different layers and also in a different layer than the input line. The solution is expanded to design different devices, such as diplexers, resonators, and multi-frequency resonators, leading to vertical filters. As the resonances are achieved by stacking resonators, the effective circuit footprint is very compact. The proposed devices can be implemented in a volumetric chip fashion, allowing integration with planar transmission line circuits and flexible output connection placement. A complete analysis of the different devices is proposed, extracting and verifying their equivalent circuit models.

Neuromorphic object localization using resistive memories and ultrasonic transducers

Real-world sensory-processing applications require compact, low-latency, and low-power computing systems. Enabled by their in-memory event-driven computing abilities, hybrid memristive-Complementary Metal-Oxide Semiconductor neuromorphic architectures provide an ideal hardware substrate for such tasks. To demonstrate the full potential of such systems, we propose and experimentally demonstrate an end-to-end sensory processing solution for a real-world object localization application. Drawing inspiration from the barn owl’s neuroanatomy, we developed a bio-inspired, event-driven object localization system that couples state-of-the-art piezoelectric micromachined ultrasound transducer sensors to a neuromorphic resistive memories-based computational map. We present measurement results from the fabricated system comprising resistive memories-based coincidence detectors, delay line circuits, and a full-custom ultrasound sensor. We use these experimental results to calibrate our system-level simulations. These simulations are then used to estimate the angular resolution and energy efficiency of the object localization model. The results reveal the potential of our approach, evaluated in orders of magnitude greater energy efficiency than a microcontroller performing the same task.

Application of Radar-Absorbing Materials for Attenuating High-Frequency Interference in the Electrical Circuits of Aircraft Electrical Systems

Conducted high-frequency electromagnetic interference is induced in the electrical circuits of aircraft electrical systems under the effect of external man-induced electromagnetic fields penetrating into the aircraft structure through radio-transparent apertures. To attenuate the impact of the conducted high-frequency electromagnetic interference induced in the two-wire lines of electrical bundles and other electrical circuits of electrical systems on sensitive semiconductor elements and integral microchips of on-board instruments and devices, low-pass filers on the basis of lumped components are used. At high frequencies, resonance phenomena may occur in the filter electrical circuits, which degrade the filter capabilities to attenuate conducted interference. Conducted high-frequency interference can be attenuated, and their propagation paths in the two-wire lines of electrical bundles and in the electrical circuits of on-board instruments and electrical system devices can be eliminated by applying radar-absorbing materials (RAM). Conducted electromagnetic interference in two-wire lines at a frequency above 1000 MHz generates high-frequency electromagnetic fields. With RAM placed in close proximity to the conductors of two-wire lines, it is possible to attenuate conducted high-frequency interference due to absorption of the interference electromagnetic field energy. The results of experimental studies are presented, the data of which make it possible to evaluate the extent to which the conducted high-frequency interference is attenuated in the frequency band 0.1–3000 MHz by applying radar-absorbing materials.

A new method to calculate corona losses for active conductors considering real transmission line unbalance

This paper shows the characteristics of an algorithm that calculates the corona losses of transmission lines. The line can have up to four circuits, with any configuration, with single or bundled conductors, and taking into account the line unbalance. This is achieved by modelling the lines in phase quantities, for active conductor, and calculating the corona losses for each one. The results are given per active conductor and average per bundle. In lines with several conductors per phase the results are given per circuit and a total one. These characteristics allow choosing the most convenient configuration and spacing for the conductor bundles, which will reduce and balance corona losses. The results found with this method show that the value of the losses calculated with the formulas with transmission lines symmetrically transposed is conservative. The configuration and the number of conductors per phase have a noted influence in the value and the asymmetry of the corona losses. In double circuit lines, corona losses can be reduced by changing the arrangement of the phases of circuit two in reference to circuit one, with the advantage that, at the design stage, those changes are costless.

A High-Performance UWB Gaussian Pulse Generator: Analysis and Design

This article aims to investigate the limitations on the amplitude of the conventional step recovery diode (SRD)-based Gaussian pulse transmitter and techniques to overcome the limits. The operation of the modified design is examined and compared with a conventional configuration. The results show a considerable increase in the pulse amplitude. The high pulse amplitude of the modified configuration represents an increase in the transmitter’s output power and its improved probing range. The Gaussian pulse is converted into the first derivative Gaussian pulse using a 90° broadband coupler as a differentiator and a semi-differentiator delay line circuit with balanced stubs. The output monopulse generated using the balanced stub delay line has more symmetric sidelobes with narrower pulsewidth than the 90° couplers. Experimental results have shown the high performance of the proposed transmitter over the conventional designs in terms of pulse amplitude and symmetry.

Distance relaying of Untransposed parallel transmission lines in case of phase-phase inter-circuit faults

• Untransposed parallel transmission lines are targeted for distance relaying. • Phase-phase inter-circuit faults are addressed in the distance relaying. • The ADALINE is developed for an accurate online estimation of the fault distance. • The proposed approach achieves fast fault tripping and an accurate fault location. • It tolerates noisy conditions and properly handles variable fault arc resistance. Distance relays at both circuits of the parallel transmission lines would miscalculate the right fault impedance during inter-circuit faults. This paper deals with the distance relaying of untransposed parallel lines in case of phase-phase inter-circuit faults. It is a challenging case compared to that of transposed lines due to the mutual coupling between all six phases of the line circuits. Considering a phase-phase inter-circuit fault with the fault arc resistance, the line circuit model is analyzed on a time-domain basis. Consequently, a mathematical equation with a linear combination of specified functions is derived. This provides a splendid opportunity to establish an ADAptive LINEar combiner (ADALINE) consistent with the equation derived. The ADALINE with its simple structure gives a fast and accurate online estimation of the fault distance, employing single-end measurements during the inter-circuit faults. Hence, achieving the fault location along with the distance protection is also made possible. The proposed approach is readily implementable without being dependent on the system configuration. It operates robustly against the dynamic fault arc resistance and tolerates the noise contamination. The simulations in PSCAD/EMTDC provide extensive sensitivity analyses validating the proposed approach performance, in respect of both the accuracy and swiftness, for various fault conditions.

Compact reconfigurable bandpass filter using quarter wavelength stubs for ultra-wideband applications

In this article, the design of a compact reconfigurable bandpass filter using quarter-wavelength open/short-ended stubs for Ultra-Wideband applications is presented. The filter has been designed using three quarter wavelength stubs. Stubs are designed for specific frequencies. At the designed frequency, the quarter-wavelength stub exhibits either bandpass or bandstop characteristics according to its short or open-circuited configuration, respectively. The proposed filter generates five passbands and twelve transmission zeros through four reconfigurable states. The direct and higher-order responses of each stub are effectively utilized to achieve five passbands, which are at 3.8 GHz – 7.8 GHz (notch band from 5.9 GHz to 6.4 GHz), 2.8 GHz − 5.9 GHz, 5.2 GHz − 8.0 GHz, 5.2 GHz – 5.88 GHz, and 1.7 GHz to 4.1 GHz. The filter is designed on FR-4 substrate and simulated in High Frequency Structure Simulator. To analytically validate the results, an equivalent transmission line circuit is extracted, and ABCD parameters have been derived. The S-parameters are derived from the ABCD parameters and plotted through MATLAB software. The designed filter is fabricated and tested. There is a good agreement between simulated and measured responses. The overall size of the filter is 24 × 15 × 0.8 mm3.

A Reconfigurable Picosecond Pulse Generator in Non-linear Transmission Line for Impulse Radar Ultrawideband Applications

This letter presents a reconfigurable picosecond (ps) pulse generator (PG) having Gaussian and monocycle pulse shapes for impulse radar ultrawideband (IR-UWB) applications. A mixed step recovery diode (SRD) topology is used in combination with a non-linear transmission line (NLTL) and pulse-shaping circuit to realize the PG. The pulse-shaping network comprises an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> differentiator embedded with a single p-i-n diode to provide two different switchable states. This PG is capable of directly switching from a Gaussian to a monocycle pulse without resorting to the increase in pulsewidth twice of the original Gaussian pulse as deployed in the previous reconfigurable PGs. The PG based on the proposed technique has a pulse duration of almost 70 ps with a promising ringing level in both cases (Gaussian and monocycle). Moreover, not only is the implementation of this technique easy, but it can also modify the pulse into other important shapes, such as the doublet and higher order Gaussian pulses. The proposed reconfigurable PG is measured in both cases, and the results are presented in each case.

Load Lines of Transistor Circuits: A Unifying Educational Approach Using Blended Learning and Flipped Classroom

The paper presents the application of the blended learning and flipped classroom principles to the teaching of the load line concept. Blended learning is a rapidly evolving approach towards the direction of actively engaging students in the learning process. Flipped classroom is a proposal, in the blended learning context, suggesting that in-class students’ activities, supported by educational material made available to them in advance, could replace the traditional pattern of lectures led by teachers followed by homework. The lesson was designed according to established design principles. The content was divided into two parts. The first part was the preparation material, which was mainly pre-existing resources. Such resources can be notes, slides, videos, etc. taking into account self-assessment tests and the difficulties faced by students on the topic. All the preparation material was available online. The second part was the in-class activities including various design and decision problems, debates and logical exercises. The students in the class worked individually and in groups also participating in a peer-review activity. The participating students on the flipped classroom approach evaluated the project with a quite positive view compared to the conventional teaching forms. The aim of this work is to present the concept and applications of the load line in a unified and mathematically straightforward manner and, at the same time, employ the blended-learning and “flipping-the-classroom” approach in order to enhance students’ understanding and learning outcomes.